"As it's currently done in most laboratories in the world, sequencing involves cloning a fragment of DNA, running it through four base-identifying reactions, separating the pieces from each reaction by gel electrophoresis, then reading each piece to determine the sequence. Even though most of the procedure has been automated, it is still far too slow, tedious, and expensive to be used on anything the size of the human genome ... The matrix is a lightweight substance that holds the DNA. The mixture is inserted in the mass spectrometer and zapped with a laser pulse at a wavelength that destroys the matrix but leaves the DNA intact, airborne, and ready for analysis. This process would take seconds, rather than the hours required to run a gel."
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